Surface Smoothing of Polycrystalline Si Waveguides With Gas-Cluster Ion Beams

1999 ◽  
Vol 597 ◽  
Author(s):  
N. Toyoda ◽  
K. K. Lee ◽  
H-C. Luan ◽  
D. R. Lim ◽  
A. M. Agarwal ◽  
...  
Keyword(s):  
Rough Surface ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Three Dimensional ◽  
Optical Loss ◽  
Surface Smoothing ◽  
Multilayered Structures ◽  
Average Roughness ◽  
Scattering Loss ◽  
Cluster Ion

AbstractPolycrystalline Si (poly-Si) waveguides offer design flexibility and multilayered structures in Si-integrated photonic devices. However, as-deposited poly-Si surfaces are rough compared with single-crystalline Si, and a rough surface causes significant waveguide scattering loss at the surface. In this study, surface smoothing of poly-Si waveguides with a gas-cluster ion beam (GCIB) was demonstrated as a new smoothing technique. As the GCIB process is a directional ion-beam process, in principle it can be applied not only to plane surfaces but also to three-dimensional or non-flat structures, such as waveguide ridges.The initial average roughness of as-deposited poly-Si films (625°C, 1 μm thick) ranged from 15 nm to 22 nm, and the grain sizes were distributed from 0.2 to 0.4μm. This rough surface was dramatically smoothed to a roughness of 1.5 nm by Ar cluster ion irradiation. From the relation between the sputtered depth and the surface roughness, the sputtered depth must be greater than the height difference of the roughness (peak-to-valley) to obtain smooth surfaces. Optical transmission losses at λ =1.54 μm were measured using cutback measurement from samples before and after the smoothing by GCIB. After surface smoothing with GCIB, the optical loss decreased from 85 dB/cm to 54 dB/cm.

Application of Cluster Ion Beam Smoothing to SiC and YBCO Surfaces

1999 ◽  
Vol 585 ◽  
Author(s):  
D. Fathy ◽  
O. W. Holland ◽  
R. Liu ◽  
J. Wosik ◽  
W. K Chu
Keyword(s):  
Surface Topography ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Cluster Ions ◽  
Microwave Surface Resistance ◽  
Average Roughness ◽  
Cross Sectional ◽  
Cluster Ion Beams ◽  
Cluster Ion

AbstractOptimization of the surface topography, especially in high-temperature superconductors (HTS) and silicon carbide is crucial for device processing. Surface smoothing in these materials was investigated using Gas Cluster Ion Beams (GCIB) capable of delivering cluster ions of ≥ 2000 Ar atoms with energies of up to 30keV. Examination of the surface topography after cluster-ion irradiation was done using cross-sectional transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results indicate that typical as-deposited YBCO films on MgO substrates have an average roughness of the order of 40 nm, and interpeak distance between 300–600 nm. Application of GCIB to the surface planarization reduces the roughness to only 10 nm. Also power handling and microwave surface resistance of the YBCO film and its relationship to surface smoothness are reported. Similar observations using bulk SiC are discussed.

Gas Cluster Ion Beam Processing of GaSb and InSb Surfaces

2003 ◽  
Vol 792 ◽  
Author(s):  
K. Krishnaswami ◽  
S.R. Vangala ◽  
B. Krejca ◽  
L.P. Allen ◽  
C. Santeufemio ◽  
...  
Keyword(s):  
Oxide Layer ◽  
Molecular Beam ◽  
Ion Beam ◽  
Total Charge ◽  
Surface Smoothing ◽  
Average Roughness ◽  
Molecular Beam Epitaxial ◽  
Cluster Ion ◽  
Gas Cluster Ion Beam ◽  
A Charge

ABSTRACTGas Cluster Ion Beam (GCIB) processing has recently emerged as a novel surface smoothing technique to improve the finish of chemical-mechanical polished (CMP) GaSb (100) and InSb (111) wafers. This technique is capable of improving the smoothness CMP surfaces and simultaneously producing a thin desorbable oxide layer for molecular beam epitaxial growth. By implementing recipes with specific gas mixtures, cluster energy sequences, and doses, an engineered oxide can be produced. Using GaSb wafers with a high quality CMP finish, we have demonstrated surface smoothing of GaSb by reducing the average roughness from 2.8Å to 1.7Å using a dual energy CF4/O2-GCIB process with a total charge fluence of 4×1015ions/cm2. For the first time, a GCIB grown oxide layer that is comprised of mostly gallium oxides which desorbed at 530°C in our molecular beam epitaxy system is reported, after which GaSb/AlGaSb epilayers have been successfully grown. Using InSb, we successfully demonstrated substrate smoothing by reducing the average roughness from 2.5Å to 1.6Å using a triple energy O2-GCIB process with a charge fluence 9×1015ions/cm2. In order to further demonstrate the ability of GCIB to smooth InSb surfaces, sharp ∼900nm high tips have been formed on a poorly mechanically polished InSb (111)A wafer and subsequently reduced to a height of ∼100nm, an improvement by a factor of eight, using a triple energy SF6/O2-GCIB process with a total charge fluence of 6×1016ions/cm3.

SPUTTERING WITH GAS CLUSTER-ION BEAMS

1996 ◽  
Vol 03 (01) ◽  
pp. 1017-1021 ◽  
Author(s):  
J. MATSUO ◽  
M. AKIZUKI ◽  
J. NORTHBY ◽  
G.H. TAKAOKA ◽  
I. YAMADA
Keyword(s):  
Ion Irradiation ◽  
Removal Rate ◽  
Ion Beam ◽  
Solid Surfaces ◽  
Silicon Surfaces ◽  
Cluster Ions ◽  
Mass Filter ◽  
Cluster Bombardment ◽  
Cluster Ion Beams ◽  
Cluster Ion

A high-current (~100 nA) cluster-ion-beam equipment with a new mass filter has been developed to study the energetic cluster-bombardment effects on solid surfaces. A dramatic reduction of Cu concentration on silicon surfaces has been achieved by 20-keV Ar cluster (N~3000) ion bombardment. The removal rate of Cu with cluster ions is two orders of magnitude higher than that with monomer ions. A significantly higher sputtering yield is expected for cluster-ion irradiation. An energetic cluster-ion beam is quite suitable for removal of metal.

scholarly journals First multispacecraft ion measurements in and near the Earth’s magnetosphere with the identical Cluster ion spectrometry (CIS) experiment

2001 ◽  
Vol 19 (10/12) ◽  
pp. 1303-1354 ◽  
Author(s):  
H. Rème ◽  
C. Aoustin ◽  
J. M. Bosqued ◽  
I. Dandouras ◽  
B. Lavraud ◽  
...  
Keyword(s):  
Solar Wind ◽  
Angular Resolution ◽  
Dynamic Range ◽  
Ion Beam ◽  
Three Dimensional ◽  
Charge Composition ◽  
Ion Distribution ◽  
Central Plasma ◽  
Cluster Ion ◽  
High Level

Abstract. On board the four Cluster spacecraft, the Cluster Ion Spectrometry (CIS) experiment measures the full, three-dimensional ion distribution of the major magnetospheric ions (H+, He+, He++, and O+) from the thermal energies to about 40 keV/e. The experiment consists of two different instruments: a COmposition and DIstribution Function analyser (CIS1/CODIF), giving the mass per charge composition with medium (22.5°) angular resolution, and a Hot Ion Analyser (CIS2/HIA), which does not offer mass resolution but has a better angular resolution (5.6°) that is adequate for ion beam and solar wind measurements. Each analyser has two different sensitivities in order to increase the dynamic range. First tests of the instruments (commissioning activities) were achieved from early September 2000 to mid January 2001, and the operation phase began on 1 February 2001. In this paper, first results of the CIS instruments are presented showing the high level performances and capabilities of the instruments. Good examples of data were obtained in the central plasma sheet, magnetopause crossings, magnetosheath, solar wind and cusp measurements. Observations in the auroral regions could also be obtained with the Cluster spacecraft at radial distances of 4–6 Earth radii. These results show the tremendous interest of multispacecraft measurements with identical instruments and open a new area in magnetospheric and solar wind-magnetosphere interaction physics.Key words. Magnetospheric physics (magnetopause, cusp and boundary layers; magnetopheric configuration and dynamics; solar wind - magnetosphere interactions)

Improvement of surface roughness by ultra-thin film deposition with oxygen cluster ion beam assist deposition

2002 ◽  
Vol 749 ◽  
Author(s):  
Noriaki Toyoda ◽  
Isao Yamada
Keyword(s):  
Surface Roughness ◽  
Morphological Evolution ◽  
Ion Beam ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Average Roughness ◽  
Original Surface ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Gas Cluster Ion Beam

ABSTRACTTa2O5 films were deposited on a rough surface (average roughness 1.3nm, peak-to-valley 14nm) and surface roughness evolutions and improvements by O2 gas cluster ion beam (O2-GCIB) assisted deposition was studied. The average roughness dramatically decreased from 1.3nm to 0.5nm after deposition of Ta2O5 films 20nm in thickness with 7 keV of O2 cluster ion beams. As there was no etching or sputtering of Ta2O5 film by 7keV O2-GCIB irradiations, O2-GCIB assist deposition realized significant improvement of surface roughness by additional deposition of Ta2O5 film whose thickness was close to the peak-to-valley of original surface. It is expected that morphological evolution of the film by GCIB assist deposition becomes completely different from conventional ion assist deposition due to energetic cluster ion impacts.

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